• 정보처리학회논문지D
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• 제19D권3호
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• pp.221-228
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• 2012

이 논문에서는 특정 단말기에 대한 독립성을 보장하고 비용의 효율성을 제공하는 새로운 단조 재공 관리 시스템을 제안한다. 지금까지 효율적인 재공 또는 재고 관리를 통해 프로세스 생산성을 향상시키기 위한 다양한 연구가 진행되어 왔으며, 특히 바코드, RFID, 영상인식과 같은 다양한 IT 기술의 접목이 시도되었다. 그러나 단조 재공 관리 환경의 특성상 이러한 접근방법은 많은 문제점을 야기한다. 따라서 이 논문에서는 기존 접근방법의 한계를 극복할 수 있는 새로운 단조 재공 관리 시스템을 제안한다. 제안 시스템은 스마트 모바일 기기의 GPS 정보를 이용하여 객체를 식별하고 객체의 위치를 정확하게 관리한다. 따라서 특별한 식별태그가 요구되지 않으며, 식별태그를 판독하기 위한 특정 단말기가 요구되지 않는다. 이를 통해 기존 접근방법의 문제점을 해결하고 전체적인 단조 재공 관리 프로세스의 생산성을 향상시킨다.

• 산업공학
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• 제11권1호
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• pp.55-66
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• 1998

Fleet sizing and distribution of empty equipments are two of the most critical problems in managing transportation system. This paper develops a cost model for sizing a fleet and establishing decentralized redistribution polices of empty equipments by building from inventory theory of multi-echelon system in hub-and-spoke network. An analytical approach to determine control variables of redistribution policies in each terminal and fleet size of the transportation system is proposed and its results are validated by simulation model. Numerical experiments are conducted with respect to parameters of the model and test results for assumptions of the model are discussed.

• 한국경영과학회지
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• 제39권2호
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• pp.97-109
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• 2014

This paper considers a reverse supply chain with simultaneous recovery of used products and manufacturing of brand-new ones. Recovered products are downgraded and have to be sold in a market different from that of brand-new products at a different price. In case of a shortage of recovered product inventory, a brand-new item, if available, can be offered at the price of a recovered product. In other words, one-way demand substitution is allowed. We address the joint decision of when to manufacture brand-new product, when to recover returned product, and how to control demand substitution to maximize the hybrid production system's profits. To this end, we propose a Markov decision Process model and investigate the structure of the optimal policy. Performance comparison is numerically implemented between the models with and without downward demand substitution option under different operating conditions of the system parameters.

• 대한안전경영과학회지
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• 제10권1호
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• pp.205-213
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• 2008

Servicizing is defined 'not as to sell the products but as to sell the functions'. This study was done on the methods for revitalization as the object items of navigation & antenna among car parts. The direct door-to-door survey was done for 101 enterprises (direct-management stores) and percentage & t-test were done for statistics. The results can be summarized like followings. First, PR on servicizing is required. Second the optimized methods can be obtained by incorporating reuse & recycling distribution systems of servicizing with the existing recovery system Reuse distribution system can be constructed rationally because inventory control is being done correct1y with the periodic recovery. Finally, as for the analysis on the relative importance of main factors of servicizing, it shows that supports & providing the concrete frame of the government & local autonomous body are important.

• 한국경영과학회:학술대회논문집
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• 대한산업공학회/한국경영과학회 1996년도 춘계공동학술대회논문집; 공군사관학교, 청주; 26-27 Apr. 1996
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• pp.477-480
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• 1996

The main objective of this research is to develop the optimal control method for a Distribution Center - multi Branch inventory distribution system. With the continuous review policy, the distribution center places an order for specific order quantity to an outside supplier, and the order quantity is replenished after a certain lead time. Also, each branch places an order for particular order quantity to the distribution center to satisfy the customer demands, and receives the replenishment after a lead time. When an out of stock condition occurs during an order cycle, a backorder is placed to the upper level to fill the unfilled demands. With these situation, variable demand and variable lead time are used for better industrial practice. Futher, actual lead times with a generic lead time distribution are used in developing the control model. Under the actual lead time model, the customer service measures actually attained for the distribution center and each branch are explained as the effective customer service measures. Thus, throughout the optimal control (using computer search procedures), we can set the desired service levels for the distribution center and each branch to produce the effective service level for each branch which is consistent with the goal level of service for each branch. At the same time, the entire distribution system keeps minimum inventories.

• 한국전자통신학회논문지
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• 제17권2호
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• pp.317-324
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• 2022

본 논문에서는 일반 캐리어의 기능을 고려하여 캐리어의 단점 및 이용할 때의 불편한 점의 내용을 토대로 보완 및 개선을 위해 다양한 편리성 기능을 가진 스마트 캐리어를 연구하였다. 스마트폰 앱을 통해 캐리어에 LED와 모터잠금장치를 설치하고 on/off로 간단하게 제어하는 블루투스 인식 및 제어기능, 로드셀 센서를 캐리어 내부에 설치하여 물품을 넣었을 때 무게를 감지하여 LCD panel에 측정된 값을 보여주는 무게감지 기능, 블루투스와 경보기를 캐리어에 설치하고, 비콘과 거리를 설정하여 설정 거리 값을 벗어나면 경보시스템이 발생하여 도난 및 분실을 방지하는 기능을 갖춘 스마트 캐리어를 제작 및 실험하였다.

• 대한산업공학회지
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• 제40권2호
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• pp.233-239
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• 2014

This paper presents an extended EMQ model which determines an optimal production run length in an deteriorating production process. The production process is subject to a random deterioration from an in-control state to an out-of-control state and thus producing some proportion of defective items. Defective items produced are re-processed in the rework process to convert them into non-defectives. Through the mathematical modeling, an optimal solution minimizing the average cost per unit time as well as minimum average cost are derived. Numerical experiment is carried out to examine the behavior of the proposed model depending on model parameters.

• 한국경영과학회지
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• 제18권3호
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• pp.151-157
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• 1993

In this paper, we investigate the effects of yield randomness for lot-sizing in a multi-stage production system. The practical importance of incorporating yield randomness into production models has been emphasized by many researchers. Yield randomness, especially in semiconductor manufacturing, poses a mojor challenge for production planning and control. The task becomes even more difficult if the demand for final product is uncertain. An attempt to meet the demand with a higher level of confidence forces one to release more input in the fabrication line. This leads to excessive work-in-process (WIP) inventories which cause jobs to spend unpredictably longer time waiting for the machines. The result is that it is more difficult to meet demand with exceptionally long cycle time and puts further pressure to increase the safety stocks. Due to this spiral effect, it is common to find that the capital tied in inventory is the msot significant factor undermining profitability. We propose a policy to determine the quantity to be processed at each stage of a multi-stage production system in which the yield at each stage may be random and may need rework.

• 산업경영시스템학회지
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• 제40권1호
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• pp.79-86
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• 2017

This research focused on deciding optimal manufacturing WIP (Work-In-Process) limit for a small production system. Reducing WIP leads to stable capacity, better manufacturing flow and decrease inventory. WIP is the one of the important issue, since it can affect manufacturing area, like productivity and line efficiency and bottlenecks in manufacturing process. Several approaches implemented in this research. First, two strategies applied to decide WIP limit. One is roulette wheel selection and the other one is elite strategy. Second, for each strategy, JIT (Just In Time), CONWIP (Constant WIP), Gated Max WIP System and CWIPL (Critical WIP Loops) system applied to find a best material flow mechanism. Therefore, pull control system is preferred to control production line efficiently. In the production line, the WIP limit has been decided based on mathematical models or expert's decision. However, due to the complexity of the process or increase of the variables, it is difficult to obtain optimal WIP limit. To obtain an optimal WIP limit, GA applied in each material control system. When evaluating the performance of the result, fitness function is used by reflecting WIP parameter. Elite strategy showed better performance than roulette wheel selection when evaluating fitness value. Elite strategy reach to the optimal WIP limit faster than roulette wheel selection and generation time is short. For this reason, this study proposes a fast and reliable method for determining the WIP level by applying genetic algorithm to pull system based production process. This research showed that this method could be applied to a more complex production system.

• 패션비즈니스
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• 제11권4호
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• pp.221-231
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• 2007

SCM system is required inter-industrial cooperation as well as inter-organizational cooperation. It means not only standardization of inter-organization but also standardization of inter-industry. SCM makes possible one circulation from fiber to retail industry in the respects of information and product flows. QR is the SCM of textile apparel industry, which satisfy customer need with least cost and maximum profit. Customer-oriented supply chain system focused on information sharing, cost reduction, inventory control, lead time reduction, quick response on customer demand. How we can measure the performance of successful SCM is issued on the approach of Balanced Scorecard which evaluates 4 perspectives such as customer perspective, internal business perspective, financial perspective, and innovation and learning perspective. This can project the blueprint of textile fashion business to right direction with vision.